It just so happens that I'm the perfect test subject for this. I don't use SD cards in my phones, so I have no bias or preconceived notions about any brand or products. I do use SD cards in my cameras, so I understand how important fast read, and more importantly fast write, speeds are for users.

So I pitted two pricey models and one budget model against each other, to see how things measured up in the real world. Armed with my trusty Nikon and a Samsung Galaxy S4, I put things to the test. Read through, and see how things worked out.

The benchmark tests

The cards used were a SanDisk 64GB Extreme (advertised as the fastest card in the world), a SanDisk 64GB Ultra (a high-end model that used to hold the speed record) and a class 4 budget SanDisk 32GB SDHC card I picked up from Amazon for $20. All three of the cards performed fine, and if you're just looking for a card that will hold your files any of the three will satisfy. If you want the best speeds, well, there is a difference -- though not as big of one as the advertisements would have you believe.

PC Benchmarks

The cards were tested via a SanDisk microSD card to SD card adapter, inserted into the SD card slot on the front of my Windows desktop. I'm running Windows 7 Ultimate, on a six-core AMDFX-6350, with 16GB of RAM. The card reader is USB 2.0, and it's pretty dusty. It's not state of the art equipment, but it plays Diablo III pretty well. The cards were tested using CrystalDiskMark 3.0.2f, with four runs in a row. The results shown are from the fourth and final run for each.

SanDisk 32GB SDHC class 4 card

First up was the 32GB budget model. For most people, this card is just fine and checks in at a nice low price. It also performs "well enough" to use for file storage, but it lags well behind in the speed when compared to the others in this test. You notice that this card is slower when taking bursts of photos (see the next section titled Real-world use).

SanDisk 64GB "Ultra"

Again, casual users will find this card more than adequate. But we see remarkable improvement in the write speeds, especially during a sequential write. The increased write speed over the previous card is noticeable when transferring files, as well as taking photo bursts.

SanDisk 64GB "Extreme"

Wow. that's a huge difference in the write speeds, and you definitely notice it when you use it. Copying songs or movies from your computer to your phone is noticeably faster than the other two models, and taking photos with burst mode enabled on my Nikon showed a huge speed increase when emptying the buffer and writing to the card. While I don't see the crazy advertised write speeds, a lot of this is from the equipment I'm using to test. The simple fact is that the new Extreme series has double the write speed during a sequential write than the Ultra series has, and is almost four times faster than a cheap class 4 card from the same manufacturer.

Smartphone benchmarks

Running benchmarks on a PC is fine and dandy, and can be a good measure of how the speed increases from one card to the next. But we're an Android blog, and the speed tests we care about are the ones we can do on our Android devices. Using the same three cards, and the SD Tools app by Veluscek Ales installed on the Galaxy S4, we put each card to the test. Once again, we ran four tests in a row, and the results you're seeing are for the fourth and final test.

SanDisk 32GB SDHC class 4 card

Respectable read speeds, but the write speed leaves a bit to be desired. If you're not trying to squeeze every bit of performance out of your phone, you'll think this is adequate. Until you transfer some files, that is. If you're like me and prefer internal storage to SD cards, speeds like this are likely a big part of the reason why.

SanDisk 64Gb "Ultra"

This is a little better, but not quite as much of a jump in write speeds as we see on the PC. The SanDisk Ultra is labeled a class UH1 card, but in this particular test it performs only slightly better than the class 4 budget card. There's still a noticeable difference when copying files to the device, but the increase in performance versus the cost is something to consider.

SanDisk 64Gb Extreme

Well hello there, Mr. Extreme. These speeds are much better than the previous models, even the UH1 class SanDisk Ultra. It's faster all around when copying files to the SD card on your device, especially from a computer. Keep in mind that these tests were performed without any setup, and my phone has been on and running for a few days. I simply ejected one card and inserted another. The system is doing what the system is supposed to do, and the speed test was running at the same time.

Real-world use

Numbers are fine, and lots of people like to see them, but what really matters is how these cards perform when doing the things you normally do. I tested each of them for a while in the phone taking photos and video, used them in my computer for a bit as a "scratch drive" to hold bits and pieces I need to write blog posts, and in my Nikon DSLR vai an adapter.

For the most part, all three of the cards worked fine, but we'll break it down a little bit.

Using in a computer

When copying files to and from the SD card inserted in my desktop, it's easy to see how much faster the SanDisk Extreme is that the other cards in this test. If you grab a folder full of pictures, notes, and other snippets the Extreme does a much better job with a lot less looking at the Windows file copy animation. Not many people will use an SD card this way, but it seemed like the best way to test the real-world performance in my computer. The same difference can be seen when using the cards in a Mac, or on a laptop or desktop running Linux. The physical media of the Extreme is just better in the way that matters for faster file copy. Unfortunately, there isn't a lot of difference between the 64GB Ultra and the $20 class 4 card.

Using in the Galaxy S4

I really noticed no difference taking pictures or shooting video. SD card speed matters, of course, but i don't think normal use (full res pictures through the S4 camera, and 1080p 30fps video) is actually pushing the limits of even the slowest card in our tests. All that goes out the window if you're running applications or a swap file from the SD card, but in normal day-today use the only real difference you'll notice is how much faster the SanDisk Extreme is when copying files to the card.

Using in a DSLR and Video camera

This was the truly telling series of tests. Taking pictures is a big part of my daily work, and I have a workflow set up just the way I like it. I walk over to my makeshift photo studio, snap as many pictures as I think I'll need, and usually use burst mode to get them quickly. Then I wait for the camera to write the memory buffer to the SD card. When you are under a deadline, that 10 seconds can feel like an eternity. After using the SanDisk Extreme, I realized it was an eternity. My 10 seconds wait (I use the class 4 card in my camera for daily use) went down to less than 5 seconds from the time I let off the shutter button until the light stopped flashing. Image quality was the same between the three cards, but the speed at which I could take the pictures in burst mode was an eye-opening difference.

in my video camera, I didn't notice any difference. I typically shoot in 1080p at 60 FPS, and the dedicated class 10 Samsung card I use handles things just fine. The SanDisk may be faster in benchmarks, but again I don't think we're pushing the limit just yet. If you have a 4K camera, you might need the speed boost for better quality -- I certainly notice a difference when using the same class 4 card I use for stills in my video camera.

Conclusion

I didn't see the advertised 90 MB/s read speeds or the 60 MB/s write speeds that SanDisk advertises. This could be my testing equipment (and a good excuse to buy a new desktop) or maybe their results are done under pristine circumstances and aren't reflective of what you or I would see.

While this is a bit disappointing, the Extreme series really is about twice as fast as the Ultra series in benchmarks, and real-world use shows a nice improvement when using the faster card. Those of you that want to squeeze every drop of performance out of their hardware should consider a SanDisk Extreme card, while the casual user can probably forego the added costs and use the Ultra series. For the budget user who just wants a place to store their files, the cheap class 4 card has been reliable for the year I've used it, and the price is much more reasonable.

Everyone is a novice, 1st observation:
to operate the 90mb write, must have on your PC desktop or Latptop. 10000rpm sata 3 HDD or SDD 9000000iops, motherboard with 6gb / s, and the adapter must also support the 100mb transfer rate, the adapter does not matter if it's USB 3.0 or Internal SD, what matters is that the rate support 100mb transfer. if any of the three requirements do not, you will never reach the 90mb write.
The 2nd observation: cell phones support micro sd uhs-1 but up to 30mb write, in the world there celulars phones to reach the 90mb write. Note: This step also applies to video and photo cameras.
3th observation: You have a 32gb usb 3.0 but with transfer rate of 35mb write and another 32gb usb 3.0 transfer rate of 90MB write. and do not expect the usb 3.0 35mb write 90mb reach. specifications should be checked at what they buy, do not be fooled by the price.
4th observation: no matter if you have i7 2600k processor or amd fx8100.
5th observation: you can have micro sd 90mb write and sata 3 ssd, but if your motherboard has 3gb / s, it will never reach the 90mb write, the more probable it is to reach the 45mb write.

This review is lacking. How do you expect to get the advertised speeds when you're not using a device that supports those speeds.
The international Galaxy SIV version with the Exynos 5 Octa is the only one at this time that supports UHS-1 speeds. So it wouldn't make much sense to buy the SanDisc extreme if you're not using that phone.

For this reason alone I really would't mind if the Galaxy Note III comes with the Upgraded Exynos 5 Oca so that using SanDisc extreme becomes more meaningful

The slower than optimal performance you are seeing are very likely the Devices, not the flash causing the slowdown. The only S4 that is capable of UHC-1 speed is the international i9500 from your own forums ( http://forums.androidcentral.com/samsung-galaxy-s4/271945-does-galaxy-s4... ). Also the SD card reader in the front of your tower may not be capable of the maximum speed of SDXC.

Thorough review i must say. The results are pretty much what i expected. The "extreme" sd card is awesome but its full potential is wasted by hardware that cant keep up. Its something you see all the time really. Whats the point a having an amazing transfer rate if all that data is going to or coming from a hard drive that cant keep up. Its the exact opposite i guess with this SD card.

Here is an example of a better benchmark. I did this on my Saicoo reader ( http://www.saicoo-tech.com/html/product/view-2326.html ) which is USB3.0 and capable of 104MB/s in UHS-1. I disabled all AV/Malware scanning and ran the bench on my Sandisk 8GB Ultra. I also ran 3 passes with CrystalDiskMark as a single pass is prone to a higher error rate than an averaged result. http://pcsites.com/bench1.jpg As you can see my Ultra results are way beyond what you got. This review, while ok for comparing that one is faster than the other, will give consumers the wrong idea of what to expect. Come on Jerry, we are enthusiasts not morons.

He provided benchmarks showing the capability of the device was limited far below its real limits. Kinda like putting a block of wood under the accelerator of a car, preventing it being pressed as far as it goes and testing its racing performance. Then he pontificated on how disappointing it was.

The 'real world' test is fine, but the benchmarks are suspect at best, and a huge smack in the face of Sandisk at worst.

They are also what most users would see if they tried to buy this SDCard. People arent going to rush out and upgrade their phone and computer just so they can get the most out of their SD card, so most people aren't going to see a huge jump in performance.

This is Android Central, not World of Sandisk. Who cares if the benchmarks were off if the review overall was positive?

Yet another lame paper hastily written for instant publication. Research was poor. How about a short list of the actual maximum speeds of the top 5 phone's actual MicroSD hardware ? No comparison of the card's performance on different phones ?

The PC card reader was inadequate, you did not do tiral on a few different model of top-tier devices, though the gear you used is probably similar to the average joe's gear, bleeding edge equipment reviews requires the right gear, if you don't have it, you should not endeavor do it.

You even have the gals to start with the following statement: [quote]It just so happens that I'm the perfect test subject for this.[/quote] and then you state, quite seriously:
[quote]I don't use SD cards in my phones[/quote]

That is a major contradiction. Illogical. Completely off. Being a non-user, a cloudy-type, and on top of that, ill-tooled in regards to hardware, you are, in fact the worst possible candidate to make serious review.

I've had nothing but bad experience with SanDisk. Last time I had a micro SD Card from them, it kept on randomly disconnecting. The customer service was horrible. Rather than getting the problem solved, I kept on getting defective card after defective card.

Don't go out in a lightning storm with your luck. SanDisk has the best reputation among SD card vendors. Anecdotally, I've had nothing but good luck with them. With all the crap, no-name vendors out there with real QC problems, SanDisk is a safe bet.

I've had similar experiences with the Ultra line of microsd cards. In just under six months I had 4 of them fail in my old galaxy S2 and galaxy tab 7 plus. Went to a PNY card and haven't had any issues with the phone. Got a Nexus 7 to replace the tablet, so that's a moot point. I've got some older Ultra SD cards that I use in some of my cameras and a few of the Ultra CF cards for my DSLR that have held up for years.

Agreed. And this applies to ANYTHING in life. To me, if I'm going to invest money in something I'm going to use for some time, I want to ensure that it'll give me the most bang for my buck. I'm not going to spend extra cash for useless frills, but I'm not going to skimp out and avoid getting something that will work best for me, either. It's all about balance and doing the homework.

There is a reason they advertise the sequential read/write speeds of any memory card and also harddrives. It's what they do fastest. So it's the ideal number to get gearhead excited and make them buy their stuff. Only to find out that the promised speed doesnt'really show.
Benchmarks are also to blame, as are the people who are constantly using them to see it they're 1bps quicker than yesterday.

In typical use, in a smartphone, your sd card gets a lot of 4k block reads/writes. That's all it does all the time. Only when you record a video, it does bigger writes and the reverse when you watch a movie. But that wasn't the bottelneck in out smartphones, was it?

The 512k block writes are indeed a lot faster, but when do you write a lot of 513k blocks? Maybe when taking a photo, make a movie or copying stuff. Not something you do all day. But the tiny bits of information, read and writen randomly on the disk, that's what matters. In that respect, the fastest card is probably worth it. It's like 4 times faster with 4k random writes. The price will probably be a bit too high to make up for the performance gain.

Wow, a lot of hostility towards Jerry over the benchmarks. So he didnt have the one device that currently supports it and didnt go out and buy a new SD reader for this review. Big deal - most people dont have these either and would see the same result. He did provide real world experience and overall his impressions were positive.

Way to focus on one line of the article and not the whole thing.

I thought this was a great review and very detailed and it tells me exactly what i need to know, which is that a regular card will do just fine until this format is more widely supported.

Lighten up guys, he didnt bash SanDisk or call them liars and specifically said that it was possible he didnt have the right equipment. And his review did not seem "rushed" in any sense given that he did three different tests on three different SD cards which, to me, sounds like a huge pain in the neck with all the swapping that must have involved.

You should be thanking him for even reviewing them at all. Most people dont know the difference and could care less.

Ya divinely good job interested in the new card now tho the Samsung ultra class 1 there pushing for 60 bucks for a32 gb saying read and write speeds at 80 any info on that would be appreciated before I buy next week :-)

I think a lot of people misunderstood the point of this article. It's not an article about how fast the extreme cards could be. SanDisk already provides that information. This article is about performance for the average Joe. Using what the average Joe has at his disposal. If I was a dolt that used an SD card in my phone(I'm joking of course, use an SD card, don't use one, it's all good) I would go out and buy the expensive international version of the S4 just so I could get the benefits of the extreme SD card. This article let's me know that the budget card would fit my average Joe needs. No if I were a photographer and needed more speed then I know for sure that the extreme card would be worth it.

Some time I benchmarked the 16GB sandisk extreme 45MB/s card I use in my Lumix G5 camera.
Starting with a USB2 port on my computer, the camera was the slowest in reading and writing when used in usb mass storage. A sandisk card reader was a lot better. Finally a usb3 card reader plugged in to usb2 port was fastest.

Then I tried the usb3 port, and everything got faster. So not only the serial bus speed was slowing things down but the usb controller hardware! Of course the usb3 reader in the usb3 port was best.

If you have a desktop computer a PCIe adaptor isn't expensive, and most laptops can be retrofitted with a card if you have apci express slot.

That's why I actually prefer just using USB OTG with my tablet... If I'm about to leave the house and I'm in a hurry to copy a movie I've just ripped or some other large file, I can just plug in my 200MB/s (sequential obviously) 32GB SanDisk USB 3.0 drive to quickly transfer the content and later read it off the USB OTG cable on the tablet.. The thing cost me $37 on Newegg... 95MB/s SD cards are a lot pricier than that.

On phones I can still understand the pinning for removable media, on tablets I just don't think it's that big a deal unless you're trying to entertain kids over a long period of time (kids + dangling stuff = bad).

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